植物根际促生细菌对蒲儿根富集铜及土壤理化性质的影响

为研究植物根际促生菌(Plant growth promoting rhizobacteria,PGPR)对蒲儿根(Sinosenecio oldhamianus)富集土壤重金属铜(Cu)的影响,通过盆栽模拟试验,分析不同Cu含量土壤中加入PGPR混合菌剂后蒲儿根生长、营养状况、Cu富集量及土壤理化性质的变化。结果表明:随着土壤Cu含量逐渐增加,蒲儿根的长势减弱,表明高浓度Cu对蒲儿根生长有显著的抑制作用;蒲儿根对Cu的富集作用主要集中在根系,仅约18%的Cu转移到地上部分;而施加PGPR混合菌剂能不同程度地增加含Cu土壤中蒲儿根的株高、根长、氮、磷、钾及根系Cu的富集量,尤其在土壤Cu含量为600 mg·kg~(-1)时PGPR混合菌剂对蒲儿根的促生作用最为明显,使蒲儿根的株高、根长分别提高了10.03、7.10 cm,蒲儿根地下部分Cu富集量在土壤Cu含量为800 mg·kg~(-1)时提高了14.01%;PGPR混合菌剂还能不同程度地提高土壤脲酶、蛋白酶、蔗糖酶、磷酸酶活性,最高分别可达80.28%、217.11%、43.26%和61.89%。研究表明,接种PGPR混合菌剂能提高蒲儿根在Cu污染土壤中的抗逆性和对Cu的富集能力,且能改善土壤性质,可作为蒲儿根修复Cu污染土壤的强化措施。

Effects of plant growth-promoting rhizobacteria on the copper enrichment ability of Sinosenecio oldhamianus and physicochemical properties of soil

The aim of this study is to evaluate the effect of plant growth-promoting rhizobacteria(PGPR)on the absorption of Cu from soil by Sinosenecio oldhamianus. Specifically, the growth, nutrition, and Cu content of Sinosenecio oldhamianus grown in soils with different Cu contents and the changes in the soil physicochemical properties were determined after adding a PGPR mixture in a pot experiment. The results showed that the growth of Sinosenecio oldhamianus slowed with the increase in the soil Cu concentration, thereby indicating that the high concentration of Cu significantly inhibited the growth of Sinosenecio oldhamianus. The Cu was mainly enriched in the roots of Sinosenecio oldhamianus, and only approximately 18% of Cu was transferred to the aboveground part. The inoculation of the PGPR mixture increased the plant height, root length, contents of N, P, and K, and amount of Cu enriched in the roots of Sinosenecio oldhamianus in soils contaminated with different concentrations of Cu. In particular, when the soil Cu concentration was 600 mg·kg^-1, PGPR increased the height and root length of Sinosenecio oldhamianus by 10.03 cm and 7.10 cm, respectively. The Cu content in the Sinosenecio oldhamianus roots increased by 14.01% in soil contaminated with 800 mg·kg^-1 of Cu. PGPR also increased the soil urease, protease, invertase, and phosphatase activities by 80.28%, 217.11%, 43.26%, and 61.89%, respectively. The results suggest that multi-function PGPR can improve the Cu resistance and Cu enrichment ability of Sinosenecio oldhamianus in Cu-contaminated soil and improve soil quality. Thus, PGPR can be considered as a means to promote the remediation of Cu-contaminated soil using Sinosenecio oldhamianus.